The Tritone: Understanding the Devil's Interval in Music

What is a Tritone?

Musical Examples

Here are practical musical examples to demonstrate the tritone interval:

The tritone is one of the most fascinating and controversial intervals in music theory. Spanning three whole tones (hence the name "tritone"), it can be described as either an augmented fourth or diminished fifth, depending on the context. This interval creates extreme tension and dissonance, earning it nicknames like "the devil's interval" in medieval times.

Historical Context and Significance

The tritone has a rich history dating back to the Middle Ages when it was considered so dissonant that it was avoided in sacred music. Composers referred to it as "diabolus in musica" (the devil in music). However, by the Romantic era, composers like Wagner embraced its dramatic potential. In the 20th century, it became fundamental to blues and jazz harmony.

Technical Construction

Interval Formulas

• Augmented fourth: 6 half-steps (e.g., C to F#)
• Diminished fifth: 6 half-steps (e.g., C to Gb)

Piano and Guitar Examples

On piano: Play C (white key) to F# (black key). On guitar: Play 6th string, 8th fret (C) to 5th string, 9th fret (F#).

Practical Applications

In Classical Music

The tritone appears prominently in works like Wagner's "Tristan und Isolde" and Saint-Saëns's "Danse Macabre."

In Jazz

The tritone substitution is a cornerstone of jazz harmony, where dominant chords are substituted by others a tritone apart (e.g., replacing G7 with Db7).

In Rock and Metal

Black Sabbath's self-titled song famously opens with a tritone (the "devil's interval"), setting the tone for heavy metal.

Progressive Exercises

Level 1: Identification

Play random intervals and identify when you hear the tritone.

Level 2: Singing

Sing the tritone after hearing a reference note.

Level 3: Composition

Create short musical phrases that resolve tritones effectively.

Common Chord Progressions

The tritone appears in many standard progressions:

• II-V-I with tritone substitution: Dm7 - Db7 - Cmaj7
• Blues progression with tritone: C7 - F7 - G7 (contains B-F tritone in C7)

Ear Training Tips

The tritone has a unique, unstable sound. Compare it to:

• Perfect fourth (more consonant)
• Perfect fifth (much more stable)

Modern Usage

Contemporary composers and producers use tritones to create tension in film scores (especially horror), jazz improvisation, and even pop music hooks.